JP5416426B2 - Radiation imaging equipment - Google Patents

Description

  The present invention relates to a radiographic imaging apparatus in which a large number of radiation sources for emitting radiation are dispersedly arranged.

  Conventionally, a radiographic image using a multi-X-ray generator that includes a multi-electron-emitting device in which a large number of electron-emitting devices are arranged and emits a multi-X-ray beam by irradiating a target with an electron beam emitted from each electron-emitting device. An imaging device has been proposed (see, for example, Patent Document 1).

  However, as in the radiographic image capturing apparatus described in Patent Document 1, an electron beam is simultaneously emitted from a large number of electron-emitting devices, and a plurality of X-ray beams are simultaneously irradiated onto a subject. Since the irradiation ranges of the plurality of X-ray beams on the upper side overlap, this causes scattered radiation, which becomes noise and degrades the image quality of the radiation image. In addition, it may be possible to drive the electron-emitting devices one by one to emit an electron beam to prevent the influence of scattered rays as described above. However, it takes time until all the electron-emitting devices are driven. It takes a long time to shoot.

  Therefore, in Patent Document 2, a radiographic imaging apparatus using a multi-X-ray generation apparatus that emits a multi-X-ray beam is proposed as in the radiographic imaging apparatus described in Patent Document 1, and Patent Document 2 is proposed. In the radiographic image capturing apparatus described in 1), the range in which the multi-X-ray beams are simultaneously irradiated is divided into two in a staggered pattern so that the irradiation ranges of the X-ray beams on the X-ray detector are not adjacent to each other. It has been proposed to prevent the influence of scattered radiation.

Japanese Patent Laid-Open No. 2007-265981 US Patent Application Publication No. 2007/0133747

  However, even if the irradiation range of each X-ray beam is controlled as in the radiographic imaging device described in Patent Document 2, the scattered radiation overlaps in an oblique direction, so that the influence of the scattered radiation is sufficiently sufficient. Can not be removed.

  Furthermore, in the radiographic imaging device described in Patent Document 2, a plurality of X-ray beams are simultaneously irradiated. However, since these plurality of X-ray beams are not necessarily the same X-ray intensity and have variations, a radiographic image is obtained. May cause unevenness. In addition, the distribution of the irradiation range of the X-ray beam is not always as designed, and if the deviation occurs, the image quality of the radiation image may be affected.

  In view of the above-described circumstances, the present invention sufficiently removes the influence of scattered radiation, and intensifies and distributes a plurality of radiations in a radiographic imaging apparatus including a radiation irradiation unit that emits a plurality of radiations as described above. An object of the present invention is to provide a radiographic imaging device that can suppress the influence of variations in the number of images.

  The radiographic imaging device of the present invention includes a radiation irradiation unit in which a large number of radiation sources emitting fan beam radiation arranged in parallel with each other having a wider divergence angle are arranged, and each radiation source of the radiation irradiation unit. Radiation image detector that detects the emitted radiation and radiation from only a part of a group of radiation sources that do not overlap or adjoin the radiation range on the radiation image detector among many radiation sources In addition, the radiation irradiation control unit controls the radiation source group to sequentially emit the radiation, and the radiation irradiation control unit controls the radiation source in a state where no subject exists between the radiation irradiation unit and the radiation image detector. Each of the radiations sequentially detected by the radiation image detector by sequentially switching the group of the radiation and sequentially irradiating the radiation image detector with radiation. An image data acquisition unit that acquires image correction data corresponding to a group of sources, and an effective region that determines an effective region having a value higher than a predetermined threshold for each of the image correction data acquired by the image data acquisition unit In the state where the subject is installed between the determination unit, the radiation irradiation unit, and the radiation image detector, the radiation source control unit sequentially switches the group of radiation sources, and the radiation image detector is sequentially irradiated with radiation. An image correction unit that sequentially detects each radiation image data corresponding to each group of radiation sources detected based on the effective area and is detected based on each image correction data. And

  In the radiographic imaging device of the present invention, the radiographic image detector includes a plurality of two-dimensionally configured charge generators that generate charges corresponding to radiation irradiation and charges that are generated in the charge generators. Connection between the array of charge storage units and each of the signal storage units, each of which is provided for each row of the charge storage units and the charge signal stored in the charge storage unit flows out, and the signal storage line and the charge storage unit corresponding to the signal line A large number of switching elements provided for each charge storage section and a control signal for turning on / off the switching elements are output, and a number of scans provided orthogonal to the signal line for each column of the charge storage sections The radiation image detector and the radiation irradiating unit are arranged so that the spreading direction of the wider fan beam emitted from each radiation source is the same as the extending direction of the scanning line. Arrangement It can be.

  Here, as the “charge storage unit”, the capacity of the charge generation layer itself may be used, or a separately provided capacity may be used.

  In addition, a charge signal is read out by sequentially outputting a control signal for turning on the switch element for each scanning line connected to the column of the charge accumulation unit within the range on the radiation image detector corresponding to the effective region, Thereafter, a control signal for sequentially turning on the switch elements is sequentially output to a plurality of scanning lines connected to the column of the charge storage unit outside the range on the radiation image detector corresponding to the effective region, and the charge storage unit It is possible to provide a scanning signal control unit for resetting.

  Further, a radiation source control unit that controls each radiation source so that the intensity of radiation emitted from each radiation source belonging to the group of radiation sources approaches based on the image correction data can be provided.

  In addition, the radiation sources are arranged so that the total pixel values obtained by adding the pixel signals at the same pixel positions of the plurality of image correction data acquired by the image data acquisition unit become the same value, and emitted from each radiation source. The fan beam divergence angle can be set to control the intensity.

  According to the radiographic image capturing apparatus of the present invention, the radiation of the fan beam is emitted from a large number of radiation sources and the surfaces having wider spread angles are arranged in parallel with each other. Since radiation is emitted at the same time only from a part of a group of radiation sources whose irradiation ranges do not overlap or adjoin, it is possible to eliminate the influence of scattered radiation due to the overlap or adjacency of many radiations . In addition, since the fan beam that spreads widely only in one direction is used as described above, the influence of scattered radiation can be further efficiently removed.

  Then, in the state where the subject does not exist, each image correction data corresponding to each group of radiation sources is acquired by the radiation image detector by sequentially switching the group of radiation sources and sequentially irradiating the radiation image detector with radiation. For each image correction data, an effective area having a value higher than a predetermined threshold value is determined, and in a state where the subject is installed, the radiation image detector is sequentially irradiated with radiation by sequentially switching the group of radiation sources. Since each radiation image data corresponding to each group of radiation sources detected sequentially by the image detector and acquired based on the effective area is corrected based on each image correction data, it is detected by irradiation of scattered radiation. Radiographic image data can be removed, and the above correction can reduce the intensity and distribution variation of multiple radiations. It is possible to suppress the sound.

  In the radiographic image capturing apparatus of the present invention, the radiographic image is so arranged that the widening direction of the wider fan beam emitted from each radiation source is the same as the extending direction of the scanning line of the radiographic image detector. When the detector and the radiation irradiation unit are arranged, the effective area and the non-effective area can be divided in units of scanning lines.

  Then, for example, a control signal for turning on the switch element is sequentially output to each scanning line connected to the column of the charge accumulation unit within the range on the radiological image detector corresponding to the effective region to generate the charge signal. Read out, and then simultaneously output a control signal for sequentially turning on the switch elements for a plurality of scanning lines connected to the column of the charge storage unit outside the range on the radiation image detector corresponding to the effective area When the storage unit is reset, the total readout time of the charge signal is shortened as compared with the case where the charge signal is read by sequentially switching all the scanning lines every time radiation is emitted from each group of radiation sources. be able to. The greater the number of scanning lines to be reset at the same time, the greater the effect of shortening the time. If the reset current does not become a problem, all the scanning lines may be reset simultaneously.

  For example, when a group of radiation sources is composed of every n radiation sources, the radiation source is switched to irradiate the radiation, and charge is read as described above, the following formula Therefore, high-speed reading is possible. In addition, the entire surface readout time in the following formula means the time required when all the scanning lines are sequentially switched to read out the charge signal, and α means the overlapping ratio of the irradiation ranges of adjacent radiation source groups. The reset time means the time taken to reset all the charge storage units.

Total readout time = {(full-page readout time) / (n + 1) × α} + (full-face reset time)
In addition, when each radiation source is controlled so that the intensity of radiation emitted from each radiation source belonging to the group of radiation sources approaches based on the image correction data, each radiation source belonging to the group of radiation sources The variation in the intensity of radiation emitted from can be suppressed.

  In addition, the radiation sources are arranged so that the total pixel values obtained by adding the pixel signals at the same pixel position of the plurality of image correction data acquired by the image data acquisition unit have the same value, and the radiation sources When the divergence angle of the fan beam emitted from is set and the intensity is controlled, more uniform radiation image data can be acquired.

1 is a schematic configuration diagram of an embodiment of a radiographic image capturing apparatus of the present invention. XZ sectional drawing of the radiation irradiation part in the radiographic imaging apparatus shown in FIG. Detailed configuration diagram of electron-emitting device Cross-sectional view of fan beam emitted from radiation source with wider divergence angle Cross-sectional view of fan beam emitted from radiation source with narrower spread angle 1 is a schematic configuration diagram of a radiological image detector in the radiographic image capturing apparatus shown in FIG. The figure which shows schematic structure of one detection part of the radiographic image detector shown in FIG. The figure for demonstrating the effect | action which switches and controls the group of a radiation source sequentially The figure which showed typically the radiographic image correction data GD, pixel signal PD, and the effective area | region R The figure for demonstrating the reading method of the range on the radiographic image detector main body 20 corresponding to the effective area | region R1, and a range other than that. Schematically illustrates a pixel signal PD _{1 to n} of the same pixel position as the plurality of radiographic image correction data GD _{1 to n} The figure which shows the composition at the time of providing plural radiation source rows

  Hereinafter, an embodiment of a radiographic image capturing apparatus of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of the present radiographic imaging apparatus.

  As shown in FIG. 1, the radiographic imaging apparatus includes a radiation irradiation unit 1, a radiation image detector 2, a radiation irradiation control unit 3, an image data acquisition unit 4, an effective area determination unit 5, and an image correction. Part 6.

  As shown in FIG. 1, the radiation irradiating unit 1 includes a large number of radiation sources 1 a that emit fan beam radiation in which surfaces with wider divergence angles are arranged in parallel to each other in a one-dimensional manner. The radiation emitted from each radiation source 1 a passes through the subject 10 and is then detected by the radiation image detector 2. Each radiation source 1 a is emitted from each radiation source 1 a and passes through the subject 10. The radiation is distributed so as to form a part of the projected image of the subject. That is, a projection image of the entire subject is formed by combining partial projection images of the subject formed by the radiation emitted from each radiation source 1a.

  In FIG. 2, the detailed block diagram of the radiation irradiation part 1 is shown. 2 is an XZ sectional view of the radiation irradiation unit 1 shown in FIG.

  As shown in FIG. 2, the radiation irradiation unit 1 includes a housing 11 that forms a vacuum chamber. In the housing 11, a multi-electron source 12 that emits a large number of electron beams, and a multi-electron source 12 that emits light. And a target 13 that emits radiation in response to the collision of the electron beam. Each radiation source 1 a is composed of a combination of one electron emitting element 15, an electron lens 16 corresponding to one electron emitting element 15, a part of the target 13, and a radiation extraction window 19. Note that the target 13 may be discretely arranged corresponding to each electron-emitting device 15.

  The multi-electron source 12 includes a substrate 14 and a large number of electron-emitting devices 15 that are provided on the substrate 14 and emit an electron beam. The driving of each electron-emitting device 15 is controlled by the radiation irradiation control unit 3. Is done.

  Further, in the housing 11, an electron lens 16 that focuses an electron beam emitted from each electron-emitting device 15 of the multi-electron source 12, and a radiation shielding plate 17 that forms the radiation emitted from the target 13 into a fan beam. And. Furthermore, a radiation extraction window 19 including a radiation transmissive film 18 that transmits radiation is provided on the wall portion of the housing 11 in the radiation emission direction. The radiation irradiation unit 1 shown in FIG. 2 shows a schematic configuration, and the number of components such as the electron emitting element 15 and the electron lens 16 and the radiation extraction window 19 corresponding to each electron emitting element 15 is omitted. It shall be.

  FIG. 3 is a diagram showing a more detailed configuration of the electron-emitting device 15. The electron-emitting device 15 in this embodiment is a cold cathode type electron-emitting device. Specifically, an insulator 32 and an extraction electrode 33 are provided on an element substrate 31 made of Si, and a tip diameter made of a carbon nanotube, a metal, or a semiconductor material is formed in a central μm-sized groove between the extraction electrodes 33. An emitter 34 of several tens of nm is formed. Then, a high voltage is applied between the target 13 (anode) and the multi-electron source 12 (cathode) by the radiation irradiation controller 3, and a voltage is applied to the extraction electrode 33 as shown in FIG. Electrons are emitted from the emitter 34. The radiation irradiation control unit 3 controls the emission of the electron beam from each electron-emitting device 15 by controlling the voltage applied to the extraction electrode 33. That is, the emission of radiation from each radiation source 1a is controlled.

  The target 13 is configured as an anode and is formed of a metal such as Cu, W, or Mo, for example.

  Each radiation source 1a including the electron-emitting device 15 and the target 13 as described above emits fan-beam radiation spreading in the Y direction. 4A shows a YZ sectional view of the radiation emitted from the radiation source 1a, and FIG. 4B shows an XZ sectional view. As shown in FIG. 4A, the radiation emitted from each radiation source 1a has a divergence angle θ1 in the Y direction and has a divergence angle θ2 in the X direction, and the relationship θ1> θ2 is established. It is a fan beam that satisfies.

  In addition, the radiation irradiation control unit 3 simultaneously outputs fan beams only from a part of a group of radiation sources 1a that do not overlap or adjoin radiation irradiation ranges on the radiation image detector main body 20 among a large number of radiation sources 1a. In addition to the emission, the radiation source 1a is controlled so that the group is sequentially switched to emit the radiation. The control method will be described in detail later.

  As shown in FIG. 5, the radiation image detector 2 includes a radiation image detector main body 20, a scan signal control circuit 23, and a signal detection circuit 24.

  As shown in FIG. 5, the radiation image detector main body 20 is provided such that a plurality of scanning wirings 21 extend in the Y direction, and a plurality of signal wirings 22 extend in the X direction so as to intersect the scanning wirings 21. A plurality of detection units 30 are provided in a two-dimensional manner corresponding to the intersections of the scanning lines 21 and the signal lines 22.

  FIG. 6 shows an example of a detailed configuration of one detection unit 30 provided in the radiation image detector main body 20.

  As shown in FIG. 6, the detection unit 30 is sensitive to the radiation emitted from the radiation irradiation unit 1, and generates a charge according to the dose of the irradiated radiation, and the sensor unit Se A charge accumulating unit Cs for accumulating the electric charge generated in step 1 and a TFT (Thin film transistor) type switch RSW for reading out the electric charge accumulated in the electric charge accumulating unit Cs.

The sensor unit Se is configured by laminating photoelectric conversion layers that absorb radiation and convert it into charges. The photoelectric conversion layer is made of amorphous a-Se (amorphous selenium) containing, for example, selenium as a main component (for example, a content rate of 50% or more). By generating a charge amount (electron-hole pair) inside, the irradiated radiation is converted into a charge. Note that the sensor unit Se may indirectly convert to radiation using a phosphor material and a photoelectric conversion element (photodiode) instead of a material that directly converts radiation such as amorphous selenium into electrical charge. . As phosphor materials, gadolinium oxysulfide (GOS) activated with Tb or Eu and cesium iodide (CsI) activated with Tl or Na are well known. In this case, radiation is converted into light by a fluorescent material, and light is converted into electric charge by a photodiode of a photoelectric conversion element using amorphous silicon or the like.

The source of the switch RSW is connected to the signal line 22, the drain of the switch RSW is connected to the charge storage unit Cs, and the gate of the switch RSW is connected to the scanning line 21.

When the switch RSW connected to the signal line 22 is turned on, an electric signal corresponding to the amount of charge accumulated in the charge accumulation unit Cs flows through the signal line 22.

  Further, as shown in FIG. 5, each signal wiring 22 is connected to a signal detection circuit 24 that detects an electric signal flowing out to each signal wiring 22, and each scanning wiring 21 is connected to each scanning wiring 21. A scan signal control circuit 23 for outputting a control signal for turning on / off the switch RSW is connected.

  The signal detection circuit 24 includes an amplifier circuit that is provided for each signal wiring 22 and amplifies an input electric signal. The signal detection circuit 24 detects the pixel signal for each pixel constituting the radiation image by amplifying and detecting the electric signal for each detection unit 30 input from each signal wiring 22 by the amplification circuit.

  The radiation image detector main body 20 and the radiation irradiating unit 1 have the same spreading direction in which the fan beam emitted from each radiation source 1a has a wider spreading angle and the direction in which the scanning wiring 21 extends (Y direction). It is arranged to be.

  The image data acquisition unit 4 acquires the radiation image data detected by the radiation image detector 2. The image data acquisition unit 4 includes the radiation image correction data detected by the radiation image detector 2 in a state where the subject 10 does not exist between the radiation irradiation unit 1 and the radiation image detector 2, The radiographic image correction data detected by the radiographic image detector 2 in a state where the subject 10 is present between the radiographic image detector 2 and the radiographic image detector 2 are acquired.

  The effective area determination unit 5 compares each pixel signal of the radiation image correction data acquired by the image data acquisition unit 4 with a predetermined threshold, and determines an area of a pixel signal having a value higher than the threshold as an effective area. Is. Note that the predetermined threshold value may be determined as appropriate, for example, 10% of the value at the center of the beam, because the influence of X-ray scattering by the detector itself and surrounding members may be cut off.

  The image correction unit corrects the radiation image data acquired by the image data acquisition unit 4 using the radiation image correction data. A plurality of pieces of radiation image data and radiation image correction data are acquired by sequentially switching the group of radiation sources 1a. Then, by adding the pixel signals at the same pixel positions of the plurality of pieces of radiation image data, one whole radiation image data is generated, and the pixel signals at the same pixel positions of the plurality of pieces of radiation image correction data are respectively obtained. By adding, one piece of whole radiation image correction data is generated, and the whole radiation image data is corrected by using the whole radiation image correction data. Specifically, the correction method is performed by multiplying the reciprocal of the added pixel signal of each pixel of the whole radiation image correction data by the added pixel signal of the whole radiation image data at the same pixel position as each pixel. .

  Next, the operation of the radiographic image capturing apparatus of the present embodiment will be described.

  First, radiation image correction is performed by emitting radiation from the radiation irradiation unit 1 without the subject 10 being disposed between the radiation irradiation unit 1 and the radiation image detector 2, and detecting the radiation by the radiation image detector 2. Data is captured.

First, under the control of the radiation irradiation control unit 3, among the many radiation sources 1 a, only the fans from only a part of a group of radiation sources 1 a whose radiation irradiation ranges do not overlap or adjoin on the radiation image detector main body 20 are simultaneously obtained. The beam is emitted, the group of radiation sources 1a is sequentially switched, and the radiation is sequentially emitted. Specifically, for example, as shown in FIG. 7, first, radiation is simultaneously emitted from a group of the radiation sources 1 a ₁ arranged every three, and the radiation image detector main body 20 is irradiated with the radiation.

  The radiation irradiated to the radiation image detector main body 20 is converted into electric charges by the sensor units Se of the detection units 30 of the radiographic image detector main body 20, and the electric charges are accumulated in the charge accumulating unit Cs. An image is recorded.

  Then, a control signal for turning on the switch RSW of the detection unit 30 is sequentially output from the scan signal control circuit 23 to each scan line 21. Then, charges are read from the detection units 30 connected to the scanning lines 21 in accordance with the control signals, input to the signal detection circuit 24 through the signal lines 22, and detected as pixel signals by the signal detection circuit 24. The

  The pixel signal detected by the signal detection circuit 24 is acquired by the image data acquisition unit 4, and the image data acquisition unit 4 generates one piece of radiation image correction data, and the radiation image correction data is transmitted to the image correction unit 6. The data is output to the effective area determination unit 5.

  Then, the image correction unit 6 stores the input radiation image correction data, and the effective area determination unit 5 compares each pixel signal of the input radiation image correction data with a predetermined threshold value, and exceeds the threshold value. A region of a high value pixel signal is determined as an effective region. FIG. 8 schematically shows the radiation image correction data GD, the pixel signal PD, and the effective region R. Information on the effective area determined by the effective area determination unit 5 is output to the scan signal control circuit 23 of the radiation image detector 2.

Next, as shown in FIG. 7, radiation is simultaneously emitted from the group of radiation sources 1 a ₂ adjacent to the radiation source 1 a ₁ by the control of the radiation irradiation control unit 3, and the radiation is irradiated to the radiation image detector main body 20. Is done.

  In the same manner as described above, the image data acquisition unit 4 generates one piece of radiation image correction data, and the radiation image correction data is output to the image correction unit 6 and the effective area determination unit 5. The radiation image correction data is stored by the above, and information on the effective area determined by the effective area determination unit 5 is output to the scan signal control circuit 23 of the radiation image detector 2.

Next, as illustrated in FIG. 7, the radiation is simultaneously emitted from the group of radiation sources 1a ₃ adjacent to the radiation source 1a _2, the next, from the group of radiation source 1a ₄ adjacent to the radiation source 1a ₃ At the same time, the radiation is emitted, the same operation as described above is repeated for each radiation emission, the radiation image correction data is stored by the image correction unit 6, and the effective region determined by the effective region determination unit 5 Is output to the scan signal control circuit 23 of the radiation image detector 2.

  As described above, first, a plurality of pieces of radiation image correction data are acquired, and information on effective areas corresponding to the respective radiation image correction data is acquired. Hereinafter, radiation image correction data acquired by emission of radiation from the group of radiation sources 1an (n = 1 to 4) is referred to as GDn (n = 1 to 4), and the radiation image correction data GDn (n = The effective area determined based on 1-4) is referred to as Rn (n = 1-4).

  Next, radiation is emitted from the radiation irradiation unit 1 in a state where the subject 10 is disposed between the radiation irradiation unit 1 and the radiation image detector 2, and the radiation is detected by the radiation image detector 2. The radiographic image data is captured by.

Specifically, as in the case of radiographic image correction data imaging described above, first, radiation is simultaneously emitted from the group of radiation sources 1a ₁ and the radiation that has passed through the subject 10 is applied to the radiation image detector main body 20. The

  The radiation irradiated to the radiographic image detector main body 20 is converted into electric charges by the sensor units Se of the respective detection units 30 of the radiographic image detector main body 20, and the electric charge is accumulated in the electric charge accumulating unit Cs, thereby subject. Ten radiographic images are recorded.

Then, a control signal for turning on the switch RSW of the detection unit 30 is output from the scan signal control circuit 23 to each scan line 21. At this time, the scan signal control circuit 23 is set to a preset effective area. A control signal is output based on the information. Specifically, first, the scan signal control circuit 23 switches the scan wirings 21 connected to the columns of the detection units 30 within the range on the radiation image detector main body 20 corresponding to the effective region R1. A control signal for turning on the RSW is outputted by sequentially switching the scanning wiring 21. For example, when the range on the radiation image detector main body 20 corresponding to the effective area R1 is the range of the hatched portion shown in FIG. 9, the scanning wiring S ₁ , the scanning wiring S ₂ , the scanning wiring S _n-3 , The control signal is output by switching in the order of the scanning wiring _Sn-2 .

  Then, charges are read from the detection units 30 connected to the scanning lines 21 in accordance with the control signals, input to the signal detection circuit 24 through the signal lines 22, and detected as pixel signals by the signal detection circuit 24. The

  The pixel signal detected by the signal detection circuit 24 is acquired by the image data acquisition unit 4, and the image data acquisition unit 4 generates one piece of radiation image data and outputs the radiation image data to the image correction unit 6. . At this time, the pixel signal corresponding to the detection unit 30 outside the range on the radiation image detector main body 20 corresponding to the effective region R1 is set to 0, and radiation image data is generated.

Then, after one piece of radiographic image data is acquired as described above, the scan signal control circuit 23 then selects a row of detectors 30 outside the range on the radiographic image detector body 20 corresponding to the effective region R1. At the same time, a control signal for turning on the switch RSW is output to all the scanning wirings 21 connected to, and the charge accumulated in the detection unit 30 is reset. For example, when the range on the radiation image detector main body 20 corresponding to the effective region R1 is the hatched area shown in FIG. 9, the scan lines _{S3 to n- 4} , the scan lines _{Sn -1} , and the scan At the same time the control signal to the wiring S _n is output.

Next, radiation is simultaneously emitted from the group of radiation sources 1 a ₂ adjacent to the radiation source 1 a ₁ , and the radiation that has passed through the subject 10 is applied to the radiation image detector main body 20.

  The radiation irradiated to the radiographic image detector main body 20 is converted into electric charges by the sensor units Se of the respective detection units 30 of the radiographic image detector main body 20, and the electric charge is accumulated in the electric charge accumulating unit Cs, thereby subject. Ten radiographic images are recorded.

  Then, the scan signal control circuit 23 turns on the switch RSW for each scanning wiring 21 connected to the row of the detection units 30 within the range on the radiation image detector main body 20 corresponding to the effective region R2. Control signals are sequentially switched and output.

  Then, charges are read from the detection units 30 connected to the scanning lines 21 in accordance with the control signals, input to the signal detection circuit 24 through the signal lines 22, and detected as pixel signals by the signal detection circuit 24. The

  The pixel signal detected by the signal detection circuit 24 is acquired by the image data acquisition unit 4, and the image data acquisition unit 4 generates one piece of radiation image data and outputs the radiation image data to the image correction unit 6. . At this time, the pixel signal corresponding to the detection unit 30 outside the range on the radiation image detector main body 20 corresponding to the effective region R2 is set to 0, and radiation image data is generated.

  Then, after one piece of radiographic image data is acquired as described above, the scan signal control circuit 23 then selects a row of detection units 30 outside the range on the radiographic image detector body 20 corresponding to the effective region R2. A control signal for turning on the switch RSW is simultaneously output to the plurality of scanning wirings 21 connected to, and the charges accumulated in the detection unit 30 are sequentially reset.

And then, emitted radiation at the same time from a group of radiation sources 1a ₃ adjacent to the radiation source 1a _2, its next radiation simultaneously from a group of radiation sources 1a ₄ adjacent to the radiation source 1a ₃ is emitted, respectively The same operation as described above is repeated with respect to the emission of radiation, and radiation image data is stored by the image correction unit 6.

  As described above, a plurality of pieces of radiation image complementary data are acquired. Hereinafter, radiation image data acquired by emission of radiation from the group of radiation sources 1an (n = 1 to 4) is referred to as HGDn (n = 1 to 4).

  As described above, four pieces of radiation image correction data GDn and four pieces of radiation image data HGDn are stored in the image correction unit 6.

Then, the image correction unit 6 generates one whole radiation image data by adding the pixel signals at the same pixel position of the four pieces of radiation image data HGDn,
One whole radiation image correction data is generated by adding the pixel signals at the same pixel position of the four radiation image correction data GDn, and the whole radiation image data is corrected using the whole radiation image correction data. Is given. Specifically, the reciprocal of the addition pixel signal of each pixel of the whole radiation image correction data is multiplied by the addition pixel signal of the whole radiation image data at the same pixel position as that pixel to perform correction.

  Then, the corrected whole radiation image data is output from the image correction unit 6, and a visible image is displayed on a monitor (not shown) or printed on a predetermined recording medium based on the corrected whole radiation image data. .

  Moreover, in the radiographic imaging apparatus of the said embodiment, the intensity | strength of the radiation inject | emitted from each radiation source 1a which belongs to the group of radiation sources 1an nears based on the radiographic image correction data GDn acquired as mentioned above approaches. In this way, each radiation source 1a may be controlled.

  In addition, as shown in FIG. 10, by adding the pixel signals at the same pixel position of a plurality of pieces of radiation image correction data GDn, one piece of whole radiation image correction data is generated, and each piece of the whole radiation image correction data is generated. It is desirable to set the interval between the adjacent radiation sources 1a of the radiation irradiating unit 1 and the spread angles θ1 and θ2 of the fan beams emitted from the radiation sources 1a so that the added pixel signals have the same value.

  In the radiographic imaging device of the above-described embodiment, the charge signal is read out only from the detection unit 30 within the range corresponding to the preset effective area, and the radiographic image data is acquired. However, the present invention is not limited to this. For example, after radiation irradiation from a group of predetermined radiation sources is performed, the radiation image correction data is acquired and then all the scanning wirings 21 are acquired. After acquiring all the pixel signals by sequentially switching and outputting the control signals, only one pixel signal in a range corresponding to a preset effective area is extracted from all the pixel signals, and one radiation image Data may be generated.

  Moreover, in the radiographic imaging device of the said embodiment, although the radiation source 1a was arrange | positioned in one dimension and comprised the radiation irradiation part, it is not restricted to this, For example, the row | line | column of the radiation source 1a is the row | line | column. A plurality of rows may be arranged in parallel in the direction (Y direction) perpendicular to the direction (X direction) extending. In addition, the paper surface thickness direction in FIG. 11 is a direction in which the rows of the radiation sources 1a extend.

  Then, as shown in FIG. 11, radiation is incident on the subject 10 from different angles from the radiation source row 40, the radiation source row 41, and the radiation source row 42. Similarly, corrected whole radiation image data may be acquired, and a tomographic image of the subject 10 may be generated based on the plurality of corrected whole radiation image data. As a method for generating a tomographic image, for example, a so-called shift and add method in which a plurality of corrected whole radiographic image data is generated by shifting according to a desired cross-sectional position of the subject and adding them is used. That's fine. By controlling the shift amount of each corrected whole radiographic image data, it is possible to generate tomographic images corresponding to the cross section 1 and the cross section 2 as shown in FIG.

  In the radiographic image capturing apparatus of the above embodiment, the radiographic image detector configured as shown in FIG. 5 is used. However, the configuration of the radiographic image detector is not limited to this, and other direct conversion types and You may make it use what is used for the conventional radiographic imaging apparatuses, such as an indirect conversion type flat panel detector and an imaging plate.

DESCRIPTION OF SYMBOLS 1 Radiation irradiation part 1a Radiation source 2 Radiation image detector 3 Radiation irradiation control part 4 Image data acquisition part 5 Effective area determination part 6 Image correction part 10 Subject 12 Multi electron source 13 Target 15 Electron emission element 16 Electron lens 17 Radiation shielding plate DESCRIPTION OF SYMBOLS 18 Radiation permeable film 19 Radiation extraction window 20 Radiation image detector main body 21 Scan wiring 22 Signal wiring 23 Scan signal control circuit 24 Signal detection circuit 30 Detection part

Claims (6)

A radiation irradiating unit in which a large number of radiation sources emitting the radiation of a fan beam arranged in parallel with each other with a wider divergence angle are arranged;
A radiation image detector for detecting radiation emitted from each radiation source of the radiation irradiation unit;
Of the multiple radiation sources, the radiation is simultaneously emitted only from a part of the group of radiation sources that do not overlap or adjoin the radiation range on the radiation image detector, and the group of radiation sources is A radiation irradiation control unit for sequentially switching and controlling to emit the radiation;
In a state where no subject exists between the radiation irradiation unit and the radiation image detector, the radiation irradiation control unit sequentially switches the group of the radiation sources, and the radiation image detector is sequentially irradiated with the radiation. An image data acquisition unit for acquiring each image correction data corresponding to each group of the radiation sources sequentially detected by the radiation image detector,
For each of the image correction data, an effective area determining unit that determines an effective area having a value higher than a predetermined threshold;
In a state where a subject is installed between the radiation irradiation unit and the radiation image detector, the radiation source control unit sequentially switches the group of radiation sources so that the radiation image detector is sequentially irradiated with the radiation. An image correction unit that sequentially detects the radiation image data corresponding to the group of the radiation sources acquired based on the effective area and is detected based on the image correction data, and sequentially detected by the radiation image detector. A radiographic imaging apparatus comprising: The radiation image detector includes a charge generation unit that generates a charge corresponding to the radiation irradiation, a charge generation unit that stores a plurality of charges generated in the charge generation unit, and a plurality of two-dimensionally arranged charge storage units. The charge that is provided for each row of the storage unit and turns on / off the connection between a number of signal lines from which a charge signal stored in the charge storage unit flows and the signal line and the charge storage unit corresponding to the signal line A large number of switch elements provided for each storage unit, and a control signal for turning on and off the switch elements are output, and a large number of scanning lines provided orthogonal to the signal line for each column of the charge storage units, With
The radiation image detector and the radiation irradiating unit are arranged so that the spreading direction of the wider spreading angle of the fan beam emitted from each radiation source is the same as the extending direction of the scanning line. The radiographic imaging apparatus according to claim 1. The charge signal is output by sequentially outputting a control signal for turning on the switch element for each scanning line connected to the column of the charge storage unit within the range on the radiation image detector corresponding to the effective region. Thereafter, control signals for sequentially turning on the switch elements are simultaneously applied to a plurality of scanning lines connected to the column of the charge storage portion outside the range on the radiation image detector corresponding to the effective area. The radiographic imaging apparatus according to claim 2, further comprising a scanning signal control unit that outputs and resets the charge storage unit.   2. A radiation source control unit that controls each radiation source so that the intensity of radiation emitted from each radiation source belonging to the group of radiation sources approaches based on the image correction data. 4. The radiographic imaging device according to any one of 3 to 3.   The radiation sources are arranged so that the total pixel values obtained by adding the pixel signals at the same pixel position of the plurality of image correction data acquired by the image data acquisition unit have the same value, and 5. The radiographic image capturing apparatus according to claim 1, wherein a divergence angle of a fan beam emitted from each radiation source is set and an intensity is controlled.   In a state where the image data acquisition unit sets a subject between the radiation irradiation unit and the radiation image detector, the radiation irradiation control unit sequentially switches the group of the radiation sources so that the radiation is the radiation image. Each of the radiation image data is acquired by extracting only pixel signals in a range corresponding to the effective area from pixel signals sequentially detected by the radiation image detector by sequentially irradiating the detector. The radiographic imaging apparatus according to claim 1.

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